This section provides background information related to the present disclosure which is not necessarily prior art.
Vehicles are known to incorporate a heating, ventilation, and air conditioning (HVAC) systems to improve the comfort of the people within the vehicle interior. The HVAC systems heat and cool air blown through an air conditioning unit (HVAC unit) using a heating heat exchanger and/or a cooling heat exchanger.
Such a HVAC unit may include a casing defining a fresh-air passage and a recirculation-air passage therein, and the recirculation-air passage may be positioned below the fresh-air passage. In such a configuration, the two passages may be in fluid communication with each other through a communication hole. At least one door is disposed inside the casing to selectively open and close the communication hole in accordance with air conditioning modes of the HVAC unit.
In a fresh-air mode, fresh air is drawn into the fresh-air passage from the outside of a vehicle to introduce the fresh air into a vehicle interior. In such an operation, when fresh-air drawn from an outside of a vehicle is cooled inside the fresh-air passage, water may be generated inside the fresh-air passage due to condensation. In this case, even if the door closes the communication hole, the condensed water may leak through a space between the door and an edge of the communication hole, which may bring undesirable results, such as leaking of water into the vehicle interior.